Teacher Universe | Learning Tools | Science Corner: Inertia Magic

Home | Learning Tools | Science Corner: Inertia Magic

Inertia Magic
Jonathan Cohen

Imagine your uncle is taking a nap on the on the couch. He stays there resting until acted upon by some external force-maybe your aunt telling him to get up.

All objects are like this. The bigger some thing is, the harder it is to get moving or to stop once it is already going. Scientists call this inertia. (in-er-sha). Inertia has two parts. One part of inertia is the property of things to remain at rest until they meet some force. The other property of inertia is the way objects stay in motion in a straight line unless they meet some other force.

You can do a great physics magic trick if you understand inertia.

Here's What You'll Need
o Strip of tag board 22 cm long and 2 cm wide
o Playing card, business card, or 3" x 5" card cut in half
o Paper cup
o Coin
o Pencil
o Tape
o Wide-mouth bottle

Here's What You Do
Bend the strip of tag board into a loop. Put the loop in the paper cup. Put the penny on top of the loop. Insert a pencil through the loop and quickly flick the loop of tag board out of the cup. Observe what happens to the penny. Try it again. Did the same thing happen? It may sound like magic, but you can explain it.

More Amazing Magic Maneuvers
Place the card (business or playing) on top of an empty bottle. Place a coin on the card. Make sure the coin is smaller than the opening of the bottle. Pull the card very quickly off the bottle. What happened to the coin? Try it again. Insert pencil or pen here and quickly pull the loop out of the cup by pulling in the direction of the dotted arrow.

Now place the same card on your fingertip. Place the coin on the card. Using your other hand, flick the card quickly and firmly. What happened to the coin? Try it again. Can you balance the coin on your fingertip? Now place the same card on your fingertip. Place the coin on the card. Using your other hand, flick the card quickly and firmly. What happened to the coin? Try it again. Can you balance the coin on your fingertip?

Home | Learning Tools | Science Corner: Inertia Magic